#pragma once

#include "Noise.h"

void Noise::Initialize(void)

{
static int _p[256] = {151,160,137,91,90,15,

	131,13,201,95,96,53,194,233,7,225,140,36,103,30,69,142,8,99,37,240,21,10,23,

	190, 6,148,247,120,234,75,0,26,197,62,94,252,219,203,117,35,11,32,57,177,33,

	88,237,149,56,87,174,20,125,136,171,168, 68,175,74,165,71,134,139,48,27,166,

	77,146,158,231,83,111,229,122,60,211,133,230,220,105,92,41,55,46,245,40,244,

	102,143,54, 65,25,63,161, 1,216,80,73,209,76,132,187,208, 89,18,169,200,196,

	135,130,116,188,159,86,164,100,109,198,173,186, 3,64,52,217,226,250,124,123,

	5,202,38,147,118,126,255,82,85,212,207,206,59,227,47,16,58,17,182,189,28,42,

	223,183,170,213,119,248,152, 2,44,154,163, 70,221,153,101,155,167, 43,172,9,

	129,22,39,253, 19,98,108,110,79,113,224,232,178,185, 112,104,218,246,97,228,

	251,34,242,193,238,210,144,12,191,179,162,241, 81,51,145,235,249,14,239,107,

	49,192,214, 31,181,199,106,157,184, 84,204,176,115,121,50,45,127, 4,150,254,

	138,236,205,93,222,114,67,29,24,72,243,141,128,195,78,66,215,61,156,180};
	for (int i = 0; i < 512; i++)

	{

		_perm[i] = _p[i & 255];

	}

	for(int i = 0; i < 12; i++)
	{
		_grad3[i] = new int[3];
	}
	_grad3[0][0] =1;
	_grad3[0][1] =1;
	_grad3[0][2] =0;

	_grad3[1][0] =-1;
	_grad3[1][1] =1;
	_grad3[1][2] =0;

	_grad3[2][0] =1;
	_grad3[2][1] =-1;
	_grad3[2][2] =0;

	_grad3[3][0] =-1;
	_grad3[3][1] =-1;
	_grad3[3][2] =0;

_grad3[4][0] =1;
	_grad3[4][1] =0;
	_grad3[4][2] =1;

	_grad3[5][0] =-1;
	_grad3[5][1] =0;
	_grad3[5][2] =1;

	_grad3[6][0] =1;
	_grad3[6][1] =0;
	_grad3[6][2] =-1;

	_grad3[7][0] =-1;
	_grad3[7][1] =0;
	_grad3[7][2] =-1;

_grad3[8][0] =0;
	_grad3[8][1] =1;
	_grad3[8][2] =1;

	_grad3[9][0] =0;
	_grad3[9][1] =-1;
	_grad3[9][2] =1;

	_grad3[10][0] =0;
	_grad3[10][1] =1;
	_grad3[10][2] =-1;

	_grad3[11][0] =0;
	_grad3[11][1] =-1;
	_grad3[11][2] =-1;


	//{1,1,0};
	/*,{-1,1,0},{1,-1,0},{-1,-1,0},

		{1,0,1},{-1,0,1},{1,0,-1},{-1,0,-1},

		{0,1,1},{0,-1,1},{0,1,-1},{0,-1,-1}};*/

}



// This method is a *lot* faster than using (int)Math.floor(x)

int Noise::FastFloor(float x)

{

	return x > 0 ? (int)x : (int)x - 1;

}



float Noise::Dot(int* g, float x, float y)

{

	return g[0] * x + g[1] * y;

}



float Noise::Dot(int* g, float x, float y, float z)

{

	return g[0] * x + g[1] * y + g[2] * z;

}



float Noise::Dot(int* g, float x, float y, float z, float w)

{

	return g[0] * x + g[1] * y + g[2] * z + g[3] * w;

}



// 3D simplex noise.

float Noise::GenNoise(float xin, float yin, float zin)

{
	// Noise contributions from the four corners.

	float n0, n1, n2, n3;



	// Skew the input space to determine which simplex cell we're in.

	float F3 = 1.0f / 3.0f;



	// Very nice and simple skew factor for 3D.

	float s = (xin + yin + zin) * F3;

	int i = FastFloor(xin + s);

	int j = FastFloor(yin + s);

	int k = FastFloor(zin + s);



	// Very nice and simple unskew factor, too.

	float G3 = 1.0f / 6.0f;

	float t = (i + j + k) * G3;



	// Unskew the cell origin back to (x,y,z) space.

	float X0 = i - t;

	float Y0 = j - t;

	float Z0 = k - t;



	// The x,y,z distances from the cell origin.

	float x0 = xin - X0;

	float y0 = yin - Y0;

	float z0 = zin - Z0;



	// For the 3D case, the simplex shape is a slightly irregular tetrahedron.

	// Determine which simplex we are in.



	// Offsets for second corner of simplex in (i,j,k) coords.

	int i1, j1, k1;



	// Offsets for third corner of simplex in (i,j,k) coords.

	int i2, j2, k2;



	if (x0 >= y0)

	{

		// X Y Z order

		if (y0 >= z0)

		{

			i1 = 1; j1 = 0; k1 = 0; i2 = 1; j2 = 1; k2 = 0;

		}

		// X Z Y order

		else if (x0 >= z0)

		{

			i1 = 1; j1 = 0; k1 = 0; i2 = 1; j2 = 0; k2 = 1;

		}

		// Z X Y order

		else

		{

			i1 = 0; j1 = 0; k1 = 1; i2 = 1; j2 = 0; k2 = 1;

		}

	}

	// x0 < y0

	else

	{

		// Z Y X order

		if (y0 < z0)

		{

			i1 = 0; j1 = 0; k1 = 1; i2 = 0; j2 = 1; k2 = 1;

		}

		// Y Z X order

		else if (x0 < z0)

		{

			i1 = 0; j1 = 1; k1 = 0; i2 = 0; j2 = 1; k2 = 1;

		}

		// Y X Z order

		else

		{

			i1 = 0; j1 = 1; k1 = 0; i2 = 1; j2 = 1; k2 = 0;

		}

	}



	// A step of (1,0,0) in (i,j,k) means a step of (1-c,-c,-c) in (x,y,z),

	// a step of (0,1,0) in (i,j,k) means a step of (-c,1-c,-c) in (x,y,z), and

	// a step of (0,0,1) in (i,j,k) means a step of (-c,-c,1-c) in (x,y,z), where

	// c = 1/6.



	float x1 = x0 - i1 + G3; // Offsets for second corner in (x,y,z) coords.

	float y1 = y0 - j1 + G3;

	float z1 = z0 - k1 + G3;



	// Offsets for third corner in (x,y,z) coords.

	float x2 = x0 - i2 + 2.0f * G3;

	float y2 = y0 - j2 + 2.0f * G3;

	float z2 = z0 - k2 + 2.0f * G3;



	// Offsets for last corner in (x,y,z) coords.

	float x3 = x0 - 1.0f + 3.0f * G3;

	float y3 = y0 - 1.0f + 3.0f * G3;

	float z3 = z0 - 1.0f + 3.0f * G3;



	// Work out the hashed gradient indices of the four simplex corners.

	int ii = i & 255;

	int jj = j & 255;

	int kk = k & 255;

	int gi0 = _perm[ii + _perm[jj + _perm[kk]]] % 12;

	int gi1 = _perm[ii + i1 + _perm[jj + j1 + _perm[kk + k1]]] % 12;

	int gi2 = _perm[ii + i2 + _perm[jj + j2 + _perm[kk + k2]]] % 12;

	int gi3 = _perm[ii + 1 + _perm[jj + 1 + _perm[kk + 1]]] % 12;



	// Calculate the contribution from the four corners.

	float t0 = 0.6f - x0 * x0 - y0 * y0 - z0 * z0;



	if (t0 < 0.0f)

	{

		n0 = 0.0f;

	}

	else

	{

		t0 *= t0;

		n0 = t0 * t0 * Dot(_grad3[gi0], x0, y0, z0);

	}



	float t1 = 0.6f - x1 * x1 - y1 * y1 - z1 * z1;



	if (t1 < 0.0f)

	{

		n1 = 0.0f;

	}

	else

	{

		t1 *= t1;

		n1 = t1 * t1 * Dot(_grad3[gi1], x1, y1, z1);

	}



	float t2 = 0.6f - x2 * x2 - y2 * y2 - z2 * z2;



	if (t2 < 0.0f)

	{

		n2 = 0.0f;

	}

	else

	{

		t2 *= t2;

		n2 = t2 * t2 * Dot(_grad3[gi2], x2, y2, z2);

	}



	float t3 = 0.6f - x3 * x3 - y3 * y3 - z3 * z3;



	if (t3 < 0.0f)

	{

		n3 = 0.0f;

	}

	else

	{

		t3 *= t3;

		n3 = t3 * t3 * Dot(_grad3[gi3], x3, y3, z3);

	}



	// Add contributions from each corner to get the final noise value.

	// The result is scaled to stay just inside [-1,1]

	return 32.0f * (n0 + n1 + n2 + n3);
}